This invention relates to a radiation-proof tamper-indicating film container.
Nowadays, most 35 mm photographic film is sold and stored in transparent canisters. This has the advantage that, once the cardboard box comprising the outer packaging of the film has been removed, essential information about the type of film contained within the canister can still be obtained without opening the canister. Furthermore, in many parts of the world, unscrupulous dealers sell, as new film, either (at best) old stock, or (at worst) film cassettes containing only the film leader strip which suggests a full roll of film where none, in fact, exists.
A transparent canister therefore enables the user to establish instantly the type of film contained therein, as well as the essential photographic information relating thereto. Furthermore, it enables the buyer to make at least a superficial examination of the film cassette in order to establish whether it has been tampered with or not.
The major short-coming of a transparent film canister is that it increase the possibility of damage to the film due to inadvertent exposure to a light source. Furthermore, a transparent container provides little or no protection from the other forms of radiation to which photographic film may be exposed. A prime example of this is the possible exposure of photographic film to X-radiation during baggage checks at airport terminals.
The potential for damage to both developed and undeveloped photographic film subjected to X-radiation is an established fact. For travellers whose baggage is subject to X-ray security screening, it represents at least four areas of concern.
Firstly, there is a possibility that the "film-safe" X-ray machines used to examine hand luggage are incorrectly calibrated or maintained, resulting in higher-than-recommended levels of X-radiation.
Secondly, as increasingly mentioned in most leading photographic texts, and as proved in extensive research by the American Society of Magazine Photographers, X-radiation is cumulative in its effect on photographic film. One or two exposures of film to X-ray screening in a "film-safe" device may well have no deleterious effect. However, for the traveller moving through a number of such X-ray checks, cumulative exposures may well damage film.
Thirdly, as instanced by the same authority, the higher the ISO rating of film (the "faster" the film is) the greater is its sensitivity to X-radiation. A "film-safe" X-ray machine calibrated not to damage conventionally rated films in the ISO 25-400 range offers no assurance of X-ray protection to the ultra-fast films of around ISO 800-2000 used by professionals today.
Finally, there exists the possibility of conventional, as opposed to "fail-safe" X-ray screening machines, being used on luggage committed to the hold of an aircraft.
While many airports issue warnings to remove all photographic film from luggage prior to it being X-rayed, others do not. Many travellers or professional photographers forget to do so and their photographic films may consequently get damaged.